<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>my css3</title>
    <style>
        .c1 {
            width: 500px;
            border: 1px solid black;
        }
        .c2 {
            width: 100%;
            visibility: hidden;
        }
        .c1:hover .c2 {
            visibility: visible;
        }

        html {
            font-size: 16px;
        }
        .c3 {
            font-size: 2rem;
        }
        .c4 {
            color: goldenrod;
            font-size: 2em;
            /*background-color: rgb(200, 100, 150);*/
            /*background-color: #12a45c;*/
            /*background-color: #0000ff;*/
            /*background-color: #9933cc;*/
            /*background-color: #93c;*/
            background-color: #7d301d;
        }
        .c5 {
            font-size: 32px;
        }
        .cl1 {
            color: #2d85f0;
        }
        .cl2 {
            color: #f4433c;
        }
        .cl3 {
            color: #ffbc32;
        }
        .cl4 {
            color: #0aa858;
        }
    </style>
</head>
<body>
<div class="c5">
    <span class="cl1">G</span>
    <span class="cl2">o</span>
    <span class="cl3">o</span>
    <span class="cl1">g</span>
    <span class="cl4">l</span>
    <span class="cl2">e</span>
</div>
<div class="c3">
    达内云计算 Cloud Computing
    <div class="c4">
        达内云计算 Cloud Computing
    </div>
</div>
<div class="c1">
    <img class="c2" src="http://n.sinaimg.cn/default/1_img/upload/3933d981/749/w930h619/20201123/af26-kefmphc8510631.jpg">
</div>
</body>
</html>